35-45mph? You are probably just now noticing how bad the gear ratios are from from 2-3-4th gear. Under normal driving the rpms drop way below 2grand into 4th at that speed, it still sucks if you have your foot in the throttle.. It lugs the engine for a few moments..especially if the mds/eco is active. Trans/engine tuning seems to be what makes a lot of guys the happiest when trying to resolve these issues. That and a stall convertor.
It's the first thinkg on my revised wishlist after watching guys on here spend thousands of dollars and still not be satisfied. The stall really changes the fun factor.